Lucas Oil 10278 Engine Oil Stop Leak - 1 Quart

This product has been negatively reviewed far too many times, and I felt compelled to write a review on it. I have used this product on 3 cars with oil leaks, and my family has used it on their cars as well. My family has had great success with minor oil leaks, and 2 of my 3 cars I have used this on resulted in their oil leaks ceasing completely. My other car turned out to be a decent sized crack in my oil pan gasket, which explains why throwing some Stop Leak at it didn't solve my issue. This product helps greatly to repair old, hardened seals, but it doesn't falsely advertise to bring about miraculous results in moderate to major issues. My point is, this product works extremely well for it's intended purposes, and I feel that all of the negative reviews should be taken with an grain of salt. It would be spectacular to hear, from the negative reviewers, what sort of issues ended up being diagnosed in the cars this product didn't help. I'm by no means trying to put down the negative reviewers, but it does get a bit frustrating reading reviews on Amazon like "Put it in my car, didn't work, still leaking, crap product" or "I contracted a flesh-eating bacteria, and this 'highly rated' Neosporin didn't work. Don't waste your time. 1 star. Booooooo!!!!" Lucas Stop Leak is a great product for it's intended purposes, has been used and trusted by amateur and professional mechanics for years, and fully deserves a solid 5 stars.

I’m a Certified Auto Tech as well as Hyundai Master Technician with over 12 years of auto tech experience. I have seen it all used it all so many products claiming to stop leaks and improve fuel mileage and boost octane blah blah blah. Lucas stop leak actually works. Now you can’t expect it to work on a mechanical failure like rotted oil pan and broken gasket but it will stop or slow down seals and gaskets that are drying out or starting to fail. Most oil leaks are from going over your oil change intervals where the oil loses its additive properties and causes seals and gaskets to dry oil and crack. I find using Lucas stop leak with a decent high mileage semi synthetic or full synthetic oil is where it works best. Do not do what you could with older cars and use 10w30 or 20w50 oils thinking cuz it’s a thicker weight it will help. You will only damage your engine. Use the recommend viscosity or u can even go from a 5w30 to a 0w30. If in colder climates like myself in CT in winter I go with a 0w20 or 0w30 in my Acura with Lucas stop leak for better cold starts as this is wear most of engine wear occurs. So a thinner cold oil weight helps it circulate faster and oil pressure to rise faster protecting ur engines internals faster. With using Lucas I go 7500 miles on my oil changes on my 07 Acura TSX with 127k miles and the oil always comes out still clean a light brown. Had a small oil leak when purchased at 63k miles and has not gotten worse since the first oil change I did. I swear by Lucas products the fuel additive top end lubricant is also amazing and adds 2mpg on average to my gas mileage as well as a better cleaner running engine.

I have a leaking intake manifold gasket and the engine needs to be removed to replace and the car has over 200,000 miles on it. Works better that it is warmer which I believe improves the viscosity of oil but it will never stop leaking.I'll let the next person decide what to do because I upgraded to a newer year and model. And, yes, to be sure, I will express all that my older car needs when I sell. The good thing is that I have maintained well enough that it will pass inspection and that was always the case. Don't know why I am shaking this but it's my post so there we are...LOL

How I arrived at my overall rating: ***** (5 stars)Value ***** (5 stars)Purchase price: $10.99Seems like a decent price for some insurance.Quality/Durability ***** (5 stars)Duration of use: 5 yearsSeems to do what its supposed to do.Ease of Use/Assembly/Install: ***** (5 stars)The bottle makes pouring it without a mess and no need for a funnel.Usefulness/Appearance/Fun Factor: ***** (5 stars)I have started using this for all older engines (>10 years or >100,000miles). I've always had older cars, and for most, at some point there will be small oil leaks around the oil pan or filter housing or head gasket. I started using this with one of my older cars at about 110,000miles and it's now at about 135,000miles and is oil free.Have not noticed any diff in mileage. Maybe engine is a little bit quieter? Not sure, but it's not louder.Will continue to use!

TL;DR Worked for my minor rear main seal leak, but you need to drive the car around for 200-500 miles for the stuff to really be effective.I went to the mechanic with my Range Rover (65k miles, regular maintenance) and discovered there was a fluid leak coming from between the transmission and the motor. They weren't sure if it was oil or transmission fluid. I added UV dye to the oil and determined that it was indeed oil. If this was the case, then the mechanic said that it was highly likely that it was the rear main seal that had failed. I read through all of the online forums and found that oil leaks are common with this model, but several people claimed that they tried Bar's Stop Leak, Lucas Stop Leak, etc. and it stopped the leak. A handful of people had a poor experience. I am most familiar with Lucas products so I chose to give this a try before spending $2000 to drop the transmission to replace the rear main seal.To my surprise, it worked. I drove it around for 50 miles and no sign of leaking. I let the car sit for a few days and there was a huge puddle of oil under the car. Discouraged, I thought it didnt work after all. I cleaned up the oil and took a drive (~200 miles) and all signs of leaking went away again. I've been checking every day and it appears that the leak is gone for now.